This invention relates to methods and devices for liquid cooling the heat sinks of engines and the like.
Gasoline and diesel powered engines are typically either cooled by convective heat transfer from the engine directly to atmospheric air, or by cooling systems which circulate fluid coolant through internal coolant passages in the engine. Engines of the former type are sometimes called "air-cooled" engines, while those of the latter type are commonly called "liquid-cooled" or "water-cooled". In indirect liquid cooling, coolants such as a mixture of ethylene glycol and water are circulated in a closed system to and from a remote radiator. In direct liquid cooling, water from a bulk source (e.g., lake or sea water in a marine application) is circulated through the engine. Most modern automobile engines have indirect liquid-cooling, while many marine engines have direct liquid-cooling. Many smaller engines employed, for instance, in motorcycle and generator applications, are air-cooled.
Air-cooled engines typically have heat sinks with extensive arrays of exposed fins to provide a significant surface area for the dissipation of heat into the atmosphere. As used herein, "fin" refers to any shape of protrusion extending from a surface for dissipating heat therefrom. As the heat-dissipating capacity of the heat sink is directly related to the surface area of the heat sink in direct contact with the air, it is common to cover as much of the heat sink with fins as is practically possible. Frequently, the fins are in the form of parallel, narrow ridges extending a substantial distance outward from the heat sink. For example, some ridge-form fins extend outward a distance more than five times their thickness, and are separated by gaps only about as wide as the fins themselves.
Although air-cooled systems may generally be considered less complicated than liquid-cooled systems due to the absence of the requisite coolant, seals and pumping means, they generally require a flow of cool air directly across the heat sink. Liquid-cooled systems can remove heat, via the liquid coolant circulated through plumbing, to convenient, remote areas for dissipation.
Air-cooled engines of various designs are commercially produced in high volumes by engine manufacturers and available for incorporation by manufacturers of engine-driven systems into the designs of their products. Cost considerations typically favor the selection of a readily available, standard engine design of high volume production for use in a new engine-driven system.